Summary:The error generally occurs due to:
Document corruption
1. Thumbnail drag the document by performing the steps mentioned in the article How to Perform a Thumbnail Drag.
2. Once you have copy of your document, perform ‘Collect for Output’.
Insufficient Permissions
1. Give full read & write permission to the document and the folder its saved in and then open it in QuarkXPress.
2. In case the document is saved on a network/external drive, move it to the local drive on the computer and then open it in QuarkXPress.
3. Perform ‘Collect for Output’ and save it locally in a folder on the machine rather than saving it to an external/network drive.
For collect for output, refer to the article How to do a Collect for Output